This invention pertains to an improved fiber optic connector with a keying element. Keying systems are known in the connector art to enable particular connectors to be intermateable with only particular receptacles. Such polarization ensures that a connector having a specific key may only be connected to a receptacle having a complementary keying configuration. In the fiber optics area, the conducting of signals for equipment, such as local area networks (LAN), require polarization of the connected fibers connecting the components. Because each connection includes an input path and an output path, and the output of one station must be correctly connected to the input of another station, it is absolutely necessary that correct polarization of all physical connections be maintained at all times. Also, it is necessary that stations be connected in proper sequence. Thus, a keying system having four keying combinations may be established for multi-mode connectors, for example, the American National Standards Institute (ANSI) has proposed under Standard X3.166-1989 a media interface connector having A, B, and (S) slave configurations wherein the slave position configuration may mate to a receptacle having any of the various keying configurations. Four different keying configurations also denote single-mode connectors: SA, SB, SM and SS. Single-mode denotes connectors which have one single optical mode or propagation state of the communication signal which results in an optical fiber core significantly smaller than for multi-mode. Multi-mode denotes connectors which have multiple optical modes in which the communication signal is propagated.
U.S. Pat. No. 5,166,995 discloses a connector assembly suitable for connecting duplex fiber optic fiber cables to each other having removable keying elements. The patent discloses three removable keying elements, each having a recess located in a different position at the top of the key. Each keying element has a post which is inserted into an aperture of the plug body. Upon insertion of the keying element into the plug body, proper polarization of the connector is obtained.
However, the aforesaid U.S. patent only discloses a connector assembly including removable keys. Such a keying element which is removable is disadvantageous because the loose keys may be misplaced and under certain circumstances may be difficult to insert in the connector. In addition, three separate keying elements require increased production and molding costs for the manufacture of the connector assembly. Therefore, an improved connector assembly that does not require loose, removable keys is needed.